1. Field of the Invention
Exemplary embodiments of the present invention relate to a communication system, and more particularly, to an apparatus for transmitting and receiving a signal capable of transmitting and receiving data by improving digital to analog modulation or analog to digital modulation performance in a communication system.
2. Description of Related Art
An apparatus for transmitting and receiving a signal in a communication system requires a wide bandwidth of several GHz so as to transmit ultra high-speed data of several Gbps or more. In order to process the signal having a wide bandwidth, the signal is processed by a single channel using an analog to digital converter (ADC) or a digital to analog converter (DAC) processing a high bit and operated at high speed. Further, the signal is processed by a plurality of channels using the analog to digital converter (ADC) or the digital to analog converter (DAC) processing a high bit and operated at high speed.
The use of analog to digital converter (ADC) or the digital to analog converter (DAC) processing a high bit and operated at high speed requires expensive components and has a very complicated structure capable of performing low-speed conversion and performing data in parallel so as to perform digital processing. The use of the analog to digital converter or the digital to analog converter easily implements a radio frequency (RF) unit, but hardly implements a digital unit or is difficult to adopt several compensation methods.
To the contrary, the use of the analog to digital converter or the digital to analog converter processing a high bit and operated at high speed has a low digital processing speed and therefore, may increase performance as maximally as possible and may be easily implemented. However, the use of the analog to digital converter or the digital to analog converter requires a plurality of baseband (BB) unit or the radio frequency (RF) unit and therefore, increases costs and is difficult to constantly maintain characteristics for a plurality of paths and increase a size.
As such, due to the problems of the apparatus for transmitting and receiving a signal using a millimeter wave, most of the apparatuses for transmitting and receiving a signal use a simple modulation type such as a frequency shift keying (FSK) type or an on off keying (OOK) type or use a differential phase shift keying (DPSK) type so as to simplify a structure of a receiving apparatus. However, when using the simple modulation type, a digital modulation speed may be degraded.
Therefore, the apparatus for transmitting and receiving a signal using a wide bandwidth, for example, the apparatus for transmitting and receiving a millimeter wave needs to have a simple structure so as to optimize digital modulation performance and reduce costs.